Contrary to a generally accepted assumption, a recently published research study concludes that lignocellulosic biomass gathered by foresting degraded lands could sustainably meet growing global energy demand as forecast in the International Energy Agency's Reference Scenario for 2030. Addressing the main concern and criticism surrounding growing crops and trees for biofuels production, doing so would avoid competing with agriculture for existing arable land and actually enhance agricultural production, as well as eliminating incentives to cut down existing forest for food or biofuel feedstock.
Moreover, adopting such a land rehabilitation-based biomass-to-fuel strategy would be no more costly than investing in alternative energy infrastructure, and would likely be much cheaper. Such an approach would have significant additional benefits, including stopping the increase and even slowly reducing atmospheric CO2, and enhancing water and soil quality and conservation, which would translate into less severe floods, droughts and soil erosion, as well as slowing or even countering desertification, according to “Sustainable global energy supply based on lignocellulosic biomass from afforestation of degraded areas,” research conducted by Jurgen O. Metzger and Aloys Huttermann of the University of Oldenburg's Institut fur Reine und Angewandte Chemie.
It's a method that's eminently practical and sustainable—if only governments, international organizations and the private sector would give it serious consideration and act, the authors maintain.
“Investment for a Biomass Scenario would be actually sustainable, in contrast to investment in energy-supply infrastructure of the Reference Scenario,” they write. “Methods of afforestation of degraded areas, cultivation, and energetic usage of lignocellulosic biomass are available but have to be further improved. Afforestation can be started immediately, has an impact in some few years, and may be realized in some decades.”
Put the Wood To It
Some 81% of the world's energy supply comes from non-renewable fossil fuel sources. According to the IEA's Reference Scenario, proven, economically recoverable reserves of oil, natural gas and coal at the end of 2007 stood at 41.6, 60.3 and 133 years of consumption at present rates, respectively, the authors note.
Meanwhile, the climatic effects of increasing atmospheric CO2 and the risks and costs of maintaining our reliance on fossil fuels are increasingly evident in ocean acidification, melting of the polar ice cap, changes in weather patterns and agriculture, and more frequent severe storms, not to mention the associated costs related to geopolitical risks, terrorism and military confrontations.
Many and varied alternative energy strategies and scenarios have been proposed to the German government. All of them, the researchers were surprised to find, assume that even though it would come with numerous benefits—essentially carbon neutral, rehabilitation of degraded land with corresponding improvements to soil, water and air quality--there's just not enough land for biomass to be a major alternative energy source.
Metzger and Hutterman set out to test this widely held assumption and concluded that it's a mistaken one. Indeed, they found that foresting lands already degraded by human activity could meet the world's growing energy demands out to 2030, at less cost and with more in the way of substantial social and environmental, as well as economic, benefits than most alternatives, findings recently published in the journal Naturwissenschaften.
“Afforestation of degraded areas is an important contribution to an integrated approach to the planning and management of land resources (UN 1992). In contrast to the present practice and to, i.e., the Alternative Policy Scenario discussed by IEA (IEA 2006a), afforestation will also improve the base of a sustainable supply with food and other necessary goods for the global population (Lal 2004). In addition, high-value jobs will be created in rural areas of developing countries, in contrast to all other scenarios presently discussed,” the authors assert.
Examining underlying assumptions, as the authors appreciate, is key to assessing research conclusions and projections. “For our global overall estimations, we used exemplarily the conversion of lignocellulosic biomass via bioslurry to synthesis gas followed by Fischer-Tropsch synthesis to give a 'biomass to liquid' (BtL) biofuel and chemicals, a process being currently in development in Germany (Fachagentur Nachwachsende Rohstoffe 2004; Fachagentur Nachwachsende Rohstoffe 2005; Dahmen et al. 2007). First production plants are expected to be realized in 2010/2011 (Plass and Reimelt 2007).
Furthermore, they postulate that the conversion of the bioslurry would be done via a high temperature process with oxygen which would yield approximately 75% of the energy content of the biomass in the form of clean synthesis gas. Of the biomass, 10 toe, processed via Fischer–Tropsch synthesis, would yield about 5 toe of synthesis products-- about 4 toe of BtL, and an additional 1 toe of valuable chemicals. Heat and electricity would be generated as by-products, the result being that the process's energy consumption could be covered completely.
“The total final energy consumption of 11,664 Mtoe in 2030 will be produced from 18,300 Mtoe of lignocellulosic biomass via 16,450 Mtoe of bioslurry and additionally 2,350 Mtoe of hydroenergy, traditional biomass—including bioethanol and biodiesel—and waste and all other renewables as assumed in the Reference Scenario,” they conclude.
“The slurry will be used comparably to oil for power and heat generation (33.4%), fuel and chemical feedstock production (36.0%), and other energy needs in industry, residential, services, agriculture as well as non-energy use (21.8%). Energy for transport, own use, and losses (8.8%) were assumed to be the same as in the Reference Scenario.”